真丝布的厚薄只用MM来说明,不用yarn count

The thickness of pure silk fabric is expressed in milimeters and not in yarn count.

The thickness of pure silk fabric can only be measured by milimeter (mm) rather than yarn count.

yarn （英尺） 是测量布的长度。对方不会问你布的厚度是多少yarn，而是多少inch. 1MM=0.039in.
不要搞混：1” = 1英寸，1’ = 1英尺。

The thickness of pure silk fabric is measured by milimeter (mm) rather than by inch.

单位面积克数吧...